The present study is designed to specify patterns of cognitive development for boys between the ages of 6 and 8 from four subcultures (middle-class and lower-class black and white subjects) on tasks representing a wide range of abilities. Multiple measures of (1) rote memory, (2) abstract reasoning, (3) ability to learn and (4) ability to spontaneously generalize or abstract from learning experiences will be given individually to subjects from the four subcultures. A combination longitudinal-cross-sectional design will be used so that effects of age, time of measurement and cohort can be estimated. Multivariate analyses will be utilized to answer questions concerning whether differences between groups are in patterns or rate of development. Finally, relationships between measures taken and school success in specific areas will be determined.